In general, a wet process corresponds to a process in which processing such as etching or cleaning is performed on the surface of a substrate such as a silicon wafer or the like by bringing a liquid chemical into contact with the substrate.
Specifically, the wet process may include an etching process which may form a thin film or a layer on the substrate by bringing liquid chemical into contact with the substrate. In addition, the wet process may include a cleaning process which may clean the thin film or the layer formed on the substrate by bringing the liquid chemical into contact with the substrate, or remove contaminants or the like formed on the substrate.
Meanwhile, as the degree of integration of semiconductor devices have been enhanced in the semiconductor field, the pattern formed on the substrate is micronized to several tens of nm level, and therefore the importance of the etching process and the cleaning process has increased.
Thus, it is the actual situation that a part of a batch type wet process which has been kept for decades due to its high productivity is replaced by a single wafer type wet process. However, in the conventional wet process, it is difficult to accurately measure or maintain the temperature of the liquid chemical or the substrate as a set temperature, and therefore there is a difficulty in ensuring the uniformity of substrate processing. Therefore, there is a need for improving this.
The background art of the invention is disclosed in Korean Patent Application No. 10-1037179 (registered on May 19, 2011, title of the invention: apparatus and method for checking of temperature controller).